I can't think of too many 100% vegan bakeries in my area, because a lot that I'm thinking of are actually just vegan-friendly... I did think of these purely vegan bakeries off the top of my head:

Cinnaholic - cinnamon rolls in Berkeley, CaliforniaWholesome Bakery - vegan, soy-, yeast- and wheat-free in San Francisco, CaliforniaPepples Donuts - cake and raised donuts in Oakland, San Francisco, and found in the SF Bay Area. (Donut Farm in Oakland is where they make the donuts, though.)

The rest don't have store fronts, but I'll have to look up their websites...

Good luck with the list! This sounds like it'll be SUPER helpful if I'm traveling! :)